Well treating apparatus



J- G. BURCH WELL TREATING APPARATUS Dec. 7, 1948.

2 Shets-Sheet 1 mmi Sept. 25, 1944 Dec. 7, 1948. J. G. BURCH 'IELL TREATING minus 2 Shuts-Shad 2 Filedv Sept 25,. 1944 M d a fl .n

Patented Dec. 7,

UNITED STATES PATENT OFFICE 2,455,556 wan. resume mana'rus Julius G. Burch, Berger, Tex.

Application September 25, 1944, Serial No. 555,026

This invention relates to new and usefulimprovements in well treating apparatuses.

Itis axiomatic that an oil well cannot produce at its maximum capacity if the poles or interstices of the formation are plugged or partially so.- It

is common for an incrustation to form on the surface of the bore of the producing formation and to infiltrate the pores, crevices and fissures of such formation, particularly in hard formations of the order of limestone. These incrustations are commonly referred to as paraffns, salt and gyp scales. Numerous methods and devices have been evolved for penetrating and or removing these incrustations, but the majority of the same give only temporary or partial relief. By tests and experiments conducted over a period of years, it has been demonstrated that successful treating to increase or restore the flow of oil involves not only penetration but uniformity of pattern and substantially complete disintegration of the hardened surface of the producing formation.

It is, therefore, one object of the invention to provide an improved well treating apparatus having an explosive charge surrounded by projectiles capable of penetrating the incrustation or clogging film in a substantially uniform pattern, as Well as substantially and completely disintegrating the face of the hard producing formation, whereby the entire incrustation or film is broken up and removed and, also, whereby the clogged face of the underlying hard formation is sumciently disintegrated to a depth or radius which will leave the face of the producing formation clean and free from clogged pores or interstices.

A particular object of the invention is to provide 8 Claims. (01. 102-20) charge, which is within the column of projectiles,

an improved well treating apparatus involving the use of projectiles which are substantially spherical in shape, substantially of uniform size and formed of vitreous or equivalent material, which willhave the effect of indenting or penetrating the incrustation and striking said incrustation -a heavy blow sufficient to set up radiating forces and at the same time bursting and disintegrating whereby the well encrustment is pulverized and cleaned off the face of the formation and the projectile is disintegrated. The advantage of disintegrating the projectile is that it is reduced to a substantially course powder which blends with the debris and can be readily bailed from the well.

An im ortant object of the invention is to provide an improved apparatus, ofxthe character de-:

scribed, wherein the sphericalfiprojectiles are stacked one upon the other in the form of a cylin drical, hollow column and in contact with each other so that upon detonation of the explosive said projectiles will be shot or impelled in a uniform radial pattern, whereby each projectile will strike the wall of the well bore at a point substantially equidistant from the points struck by its surrounding or adjacent projectiles; and whereby the entire area ofthe incrustation and the face of the hard formation will be uniformly indented or penetrated and impinged upon at equidistant points in such proximity that the radial forces engendered by the bursting of each projectile will overlap the eflective area of each other adjacent projectile, with the result that uniform disintegration will take place,

Another object of the invention is to provide an improved apparatus, of the character described, wherein the power or force of the explosive is harnessed to drive projectiles against the wall of a well, whereby the effectiveness of a small quantity of saidharnessed explosive is incomparably greater than that of a larger quantity of unharnessed explosive: the power of the explosive being preferably harnessed by placing the same in a column and disposing projectiles therearound in surrounding relationship and in substantially intimate contact with the column.

A further object of the invention is to provide an improved apparatus, of the character described, wherein a plurality of individual, unconnected projectiles of substantially uniform size and spherical contour are equally spaced within a cylindrical, hollow column concentrically surrounding a small column of explosive, whereby the projectiles have a common or uniform relationship to the explosive and the force of the latter will be applied equally to said projectiles so as to simultaneously impel the same radially outward in a uniform pattern.

A construction designed to carry out the invention will be hereinafter described together with other features of the invention.

The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawing, wherein an example of the invention is shown, and wherein:

Fig. 1 is a longitudinal, vertical section through awell showing a well treating apparatus constructed in accordance with the invention, suspended therein preparatory to being exploded.

Fig. 2 is an enlarged fragmentary elevation, partly in section, of one section or shell of the apparatus and its connection to adjacent secpartly in elevation, showing the coupling and juncture between adjacent sections of the apparatus.

Fig. 4 is an enlarged view, partly in section and partly in elevation, showing the, supporting shoe which is placed on the lowermost section or shell,

Fig. 5 is a perspective view of the lower portion of the projectile carrier and explosive container which forms a part of each shell,

Fig. 6 is a horizontal, cross-sectional view through one of the shells, taken on the line 8-5 of Fig. 3, and

with their centers substantially equidistant; and

Fig. '7 is a horizontal, cross-sectional view,

taken on the line 1-1 of Fig. 8.

In the drawings, the numeral ll designates a section or shell, of which several are used in a string in treating a well. Each shell includes an outer cylindrical jacket or sleeve ll. open at both ends, and preferably formed of thin cardboard, or other suitable paperboard, similar to an ordinary mailing tube. This jacket may be waterproofed, or could be made of a suitable plastic, or any other material found expedient for the purpose, such as hail screen or tin. A projectile carrier or explosive container I2 is concentrically disposed within each jacket and is preferably made of thin tin (commercial), plastic or any other material suitable for the purpose. Both the jacket H and the carrier l2 should be made of material which will readily disintegrate when the shell explodes so as not to leave any debris which may have to be cleaned out of the well. The carrier includes an upright cylindrical sleeve l3 having an outwardly-directed, circular flange l4 at the bottom thereof, which flange is of such diameter as to snugly fit within the lower end of the jacket II, as is best shown in Figs. 3 and 4. The sleeve I3 is considerably less in diameter than the jacket ll so as to provide an annular space lltherebetween, the bottom of which is closed by the flange H. The latter telescopes the sleeve sufliciently to provide space for a bottom circular disk It which preferably has its undersurface substantially flush with the lower end of the jacket.

This disk may be formed of the same material as the jacket and it is preferable to fasten said disk to said jacket by suitable means, such as paper tape liil (Fig. 3). Each sleeve I I may be of slightly greater length than its surrounding jacket ll so as to project a slight distance above the upper end of said jacket. Thus, when a plurality of shells are fastened together, the weight will be carried by the metallic sleeves instead of the jackets.

Each shell l0 may be made several feet in length and satisfactory results have been obtained from a shell substantially 5 feet in length; however, the invention is not to be limited to any particular length and the shell may be made as short or as long as is practicable and depending upon the length of the formation to be treated or cleaned. The annular space I5 is of such width or diameter as to receive a column of individual spherical projectiles II. The elements of the shell should be so proportioned that projectiles of a given size when stacked in said annular space, will rest upon and engage each other and whereby the projectiles in any horizontal row will be in contact with each other. Thus, if each projectile is substantially of an inch in diameter, the annular space will be a fraction of an inch wider than such diameter so that the projectile may be readily dropped into the space and the projectiles of each row will be in contact or closely spaced.

also that each projectile preferably be held in engagement with the outer surface of the sleeve by the inner surface of the jacket. although each projectile might be spaceda slight distance from said sleeve with some measure of success. 0! course, the projectiles of each row are offset relative to the projectiles of adjacent rows. whereby the projectiles of every other or alternate row are in vertical alinement and whereby each projectile is engaged by six projectiles. two projectiles each in the same, overlying and underlying row's. It is pointed out that the lowermost row of projectiles will rest upon and be supported by the flange ll of the sleeve I 3, while an annular, paperboard collar or washer i'll engmes within the upper end of the annular space II for confining said projectiles therein and may be secured to the jacket by suitable means, such as paper tape I'll.

This inventionhas progressed by trial and test in many wells, and experiments have been conducted with projectiles of various sizes, shapes and materials. It has been definitely established that the shape, composition, relationship and disposition of the projectiles are critical, if the best results are to be obtained. when projectiles composed of metal were used, it was found that the same merely punctured the incrustration and indented the face of the hardformation with substantially little or no disintegration of the clogged surfaces, particularly, if said projectiles were pointed or elongated. Even'with spherical metallic projectiles it was found that the resistance offered by the incrustation was insufilcient to prevent too deep penetration and therefore the desired bursting and disintegrating of the encrustment was not obtained. In addition, it was found that the fprojectiles should be made of somematerial which would give sufficient penetratlon, but which was frangible, and which would give an explosive effect when the projectile reached a critical depth or penetration. However, this alone was not sufficient, it was also discovered that the radialforces exerted by the' disintegration. of the projectiles should be overlapping, or at least substantially contacting areas and this led to' the. necessity of a definite pattern, whereby uniform spacing of the impacts of the projectiles would result'in order that the entire incrustation be completely broken up and a complete disintegration of the face of the hard formation be obtained.

In order to obtain a uniform pattern, it was also found essential to employ unconnected projectiles which would be impelled individually by the force of the explosive. In addition, maximum efficiency of the explosive is realized only when the projectiles tightly engage said explosive or the container within which the same is disposed, thereby, in effect, harnessing the power of the explosive and eliminating damaging of said projectiles by detonation.

The foregoing tests and experiments led to several conclusions. The projectiles should be formed of some relatively hard material which would be frangible, although capable of penetrating to the required depth, and which would completely disintegrate and create the necessary expansive force in all directions upon disintegration after such penetration. A vitreous material of the order of a plastic, such as glass, was found satisfactory and good results may be obtained by the use of any plastic or ceramicsuitable for plished. which do the actual work.

the purpose. However. it was found that the character of the material alone would not satisfy the requirements. Broken glass was found to be objectionable, because of its irregular shape which caused the projectiles to frequently contact the wall of the well with their flat surfaces or with their pointed projections and, thus. fail to give uniform disintegration or substantially any disintegration at all. It was found that maximum results were achieved by the use of substantially spherical or globular projectiles, preferably of a uniform size and symmetry. Therefore, glass marbles are preferable, although an equivalent material of substantially uniform size and spherical shape may be used. Glass marbles which are solid are preferable, however, so long as the material composition of each projectile is ample to give the desired result, such a pro ectile would be satisfactory. The glass projectiles of substantially uniformv size and symmetrical contour are entirely unconnected by any type of bond so as to be individually impelled by the explosive. Also the projectiles are preferably disposed uniformly relative to the explosive and equally spaced relative to one another, thereby providing a uniform pattern with overlapping areas of disintegration upon being impelled and/or penetrating the wall of the well. Regardless of the quantity of explosive, the detonation of a high velocity explosive will not break, crack, burn or in any way damage the glass projectiles or marbles when the same are held tightly against the bare explosive or its container. Upon detonation, the projectiles become a part of the explosion and are propelled unharmed radially outwardly at approximately the speed of detonation. whereby said projectiles harness and direct the force of said explosion to the work to be accom- However, it is the projectiles alone By placing the glass projectiles ll in a uniform arrangement in the annular space It, said projectiles will, when projected as shot from the shell, strike the formation in a uniform pattern. Owing to the expansive force of the explosive charge, the projectiles will readily indent or penetrate the flow retarding wall substance or paraffin film and engage or impact the hard formation before fracturing or disintegrating. The point of initial contact between each projectile and the wall of the well bore is a relatively small one, because of the spherical exterior of said projectile and is somewhat similar to the contact which occurs when a metallic member is struck with a ball-nose hammer. After the projectile has penetrated the surface of the hard formation to a point at which the resistance offered by the incrustation or formation becomes critical to the impelling force, said projectile will dissipate its energy by violently bursting and disintegrate so completely and so suddenly that it will be reduced to finely-divided particles, such as a substantially coarse powder, which will be impelled with blasting effect in all directions under sufficient force to disintegrate the entire surface of the formation coming within its sphere of action and, of course, at-the same time, will disintegrate the incrustation or paramn film. These spheres or areas of disintegration will either overlap or expand into such close relation as to break down the entire clogged surface of the hard formation.

For exploding the shells in and projecting or impelling the projectiles or marbles IT, a suitable explosive charge I8 is placed within the sleeve ll of each carrier II. It is desirable to employ liquid nitro-glycerin enclosed within a cylindrical container ll and this container may be supported by the circular flange II. The quantity of the explosive charge should not be sufilcient to pulverize the wall of the well bore nor to force the paramn or congealed particles into the pores of the producing formation, but sufncient to drive the projectiles into or indent the surface of said formation. In order to equalice the pressures externally and internally of the shells, suitable openings or ports and II are formed in each jacket II and sleeve l3, respectively, adjacent the upper and lower ends thereof. Thus, the well fluids may freely enter the shells and possible collapse of the same is obviated.

A cylindrical shoe 22, of tin or other sheet metal or thin material, is provided for the lower end of the string and has a transverse, circular partition 23 at its lower portion (Fig. 4). The partition may be secured in position by being soldered or otherwise fastened within an internal, annular groove or recess 24 formed by providing annular overlying and underlying beads 25 and 2' in the internal surface of the shoe wall. A conical point or tip 21, having an open lower end, is disposed at the lower end of the shoe below the partition 23 and has pressure-equalizing openings 2|, similar to the ports 20 and 2|, adjacent said portion. For supporting the shoe 22, a pair of diametrically-opposed, flat eye brackets 29 are riveted or otherwise secured to the upper end of said shoe. As is clearly shown in Fig. 4, the lowermost shell It has its lower end inserted within the top of the shoe so that the disk ll of said shell rests upon the portion 23.

In order to hold the shells in alinement and facilitate assembly of a string of shells for treating a well, a cylindrical coupling collar. 30 is interposed between adjacent shells and is preferably. made of commercial tin or other suitable thin material. The ends of adjacent shells are telescoped within each collar 30 and a disk II, similar to and of the same or similar material as the disk it, is positioned within the collar between the sleeve ll of the lower shell and the disk It of the upper shell (Fig. 3). Since the sleeve ll projects a slight distance above the jacket Ii, the disk II will engage the upper end of said sleeve and be spaced from said jacket so that the weight of the superimposed or upper shell will be carried by the metallic sleeve of the lower shell. An annular, internal bead 32 is formed in the wall of each collar, at substantially midheight thereof, by crimping or grooving its exterior and the intermediate disk II is disposed in substantial horizontal alinement with the head due to the telescoping of the shell ends within said collar. As shown in Fig. l, a time bomb 3! is disposed within the uppermost shell In which consists only of the jacket II and acylindrical cap member 34, somewhat similar to the collars 23,1? over and closes the upper end of said In assembling a string of shells ill for running or lowering within a well bore, one end of a loop of tie wire 35 is connected or tied to each eye bracket 29 of the shoe 22 and the loop is of suf-- ficient length to accommodate all of the shells desired to be run. Before being tied, the loop is threaded over an insulating or non-conductive, rotatable spool or pulley It which forms a part of a bail 31. As is clearly shown in Fig. 1,

7 a 1 the bail I! may be detschably eng d by a'hook 8. which is secured to the lower end of a wire line or shooter's wire 8| and this wire line or said ball may be suspended from the derrick (not shown) in the usual manner. 'With the shoe at the upper end or mouth of the well, the lowermost shell, without the explosive charge II. is inserted within the upper end of said shoe. These parts are then lowered a few feet into the well. for convenience. and the explosive charge or its container II is then placed within the sleeve ll of the carrier II. One of the disks Ii is laid over the top of this lowermost shell andone of the collars 8| is telescoped upon said shell until the upper end of the jacket ll of the sam substantially engages the bead I! (Fig. 3)

For fastening the collar to the loop 3|, two pair of small openings ll (Fig. 7) are formed in the bead of said collar at diametrically-opposed portions thereof and a short wire I projects through each pair of openings so as to encircle one leg of said loop when the ends of the wire are twisted together. Thus, the collar will be fastened to the loop and will be held against rotation. Another shell is then inserted within the upper end of the collar so as to rest upon the previously inserted disk'Il. Upon lowering of the aforesaid assembled parts, an explosive charge may be placed within the second shell and be'followed by another disk and collar which is fastened to the loop in the manner hereinbefore described. The other shells and collars are assembled in the same way and the cap 34 is placed upon the uppermost shell which contains the time bomb II. Although not clearly illustrated, the cap 34 is adapted to be connected to the legs of the loop II in the same manner as thecollars and is provided with a similar head and wires, designated generally by the numeral 42. A strip 43, of paper tape or other material, may encircle the upper end of the cap for holding the ball 31, which overlies said cap, in vertical alinement therewith.

With the string assembled as shown in Fig. 1, the ball is supported solely by the detachable engagement of the hook 38 therewith and said string is lowered into the well bore to the point desired to be treated. which has been illustrated as at or adjacent the bottom of said well bore. When the string is positioned at the desired elevation or point, the hook may be released from the bail by merely letting a slack occur in the wire line 39 and the time bomb 83 will be detonated in accordance with the setting thereof or by any of the well-known means of detonatin bombs in wells.

The marbles or projectiles i'l, surrounding the explosive charge in the manner illustrated, will not be injured by the explosion and will be impelled radially by the expanding gases. Glass marbles have been found preferable, because glass possesses a degree of elasticity and will deflect somewhat when arrested by the hard formation. Thus, when each marble is fractured, it creates energy in the form of an expansive or bursting force which may be referred to as a "sunburst. The force of the impact is so great and the arresting of the marbles is so sudden that a complete disintegration of the incrustation and the face of the producing formation is effected. All matter thus disintegrated or loosened will fall to the bottom of the well and can be readil cleaned out. The clean producing formation is then unobstructed and is given an opportunity to produce oil to its maximum capacity.

1th pointed out that oil and gas wells have been reconditioned successfully by the herein described apparatus which employs high velocity explosives as a propellant and spherical vitreous marblesorpelletsofuniformsiseascleaningor rating projectiles. Although the applratus is primarily designbd for use in cleaning congested porosity on the surfaces of producing formations or pay sections. it has been successfully used in knock downshattered formations which may be interlocked on the irregularities of a shot hole made by the virgin shot, to destroy liners by shredding the same. to ream and underream the desired length of a producing formation. to clean water-flood and imput, repressuring wells and to reopen desired sectionsof forms tion squesee jobs within inches. Due to the w curacy with which the disintegrating effect of the apparatus may be controlled, said apparatus has been successfully and safely used for the foregoing purposes. pen and untamped, and within inches of both cemented and uncemented liners and easing shoes.

As has been hereinbeiore set forth, the fundamental principle which governs the operation of the apparatus is that the force of the explosive is harnessed or controlled so as to drive pellets or marbles against the wall of the well as projectiles. The effectiveness of a small column of explosive used to drive projectiles is incomparably greater than that of a larger column of explosiv which is unharnessed. The efficiency of the apparatus is not increased. however. by using a larger column of explosive to drive the projectiles, because said projectiles attain a velocity approximately equal to the speed of detonation of the explosive used, and this is constant irrespective of the size of the column. Attention is directed to the fact that the operation of the apparatus should not be confused with the power effect of bulk shots of explosives. As has been pointed out, the

effect of the preferred form of apparatus is to harness the force or power of the explosive and to direct the same through the projectiles to the work to be accomplished; however, the projectiles alone accomplish the actual work. Due to the disposition of glass marbles to disintegrate the formation with blasting eflect, the use of the same as projectiles is preferable and more desirable than other types of material which may be effectively employed.

The marbles or projectiles reach the wall of the well with such high velocity that the same penetrate the formation, the distance of penetration depending upon the nature of said formation and the size of said projectiles. The average depth of pentration of the. preferred fiveeighth inch projectile is one inch in hard lime, and this depth is greater than the zone of congested porosity in any well unless its porosity has been congested to a greater depth by the misuse of artificial pressuring. Therefore, one shot with this apparatus is ordinarily sufficient. When the resistance of the formation checks the movement of the frangible projectiles, the same dissipate their energy by bursting violently, disintegrating with blasting eflect toward the center of the well bore with a force greater than that of an equal amount of imbedded explosive. Obviously, glass spheres or marbles are the most effective type of projectile.

The presence of oil or water in a well has no material effect or influence upon the velocity of the projectiles. The latter effectively reach the surfaces on the wall of the well, which no other 'tool or method can reach and clean. The major portion of the force of the explosion is exerted in the uniform propulsion ofthe projectiles and not directly upon the wall of the well. All incrustrations on the face of the producing formation are thrown into the bore of the well by the projectiles penetrating and distintegrating within the wall formed by said formation face.

a The foregoing description of the invention is explanatory thereof and various changes in the size, shape and materials, as well as in the details of the illustrated construction may be made, within the scope or the appended claims. 1tgithout departing from the spirit of the inven- What I claim and desire to secure by Letters Patent is:

1. A shell for treating wells including,a tubular enclosure, an explosive charge extending longitudinally of and disposed concentrically within and spaced from the enclosure so as to provide a substantially annular space therebetween, a substantially annular column of projectiles within said space, and means confining the projectiles within said space, each projectile having a substantially spherical body of frangible material adapted to burst and disintegrate upon penetration of a well wall.

2. A shell for treating wells including. a tubular enclosure, an explosive charge extending longitudinally of and disposed concentrically within and spaced from the enclosure so as to provide a substantially annular space therebetween. a substantially annular column of projectiles within said space, each projectile having a substantially spherical body of vitreous material frangibl upon penetration of a well well and adapted tofburst and disintegrate upon such penetration.

3. A shell for treating wells as set forth in claim 2 wherein the projectiles are arranged in the column in a closely spaced substantially uniform pattern.

4. A shell for treating wells as set forth in 2 wherein the projectiles comprise glass bles.

5. A shell for treating wells including, an e!- plosive core, a cylindrical column of glass mnbles concentrically surrounding the core and disposed in substantially uniform inter-engaging 10 relation, a cylindrical jacket surrounding and confining the columnof marbles in close proximity to said core, and means supporting said column of marbles.

6. A shell for treating wells including, a sleeve, an explosive charge within the sleeve, 9. jacket concentrically surrounding and spaced from said sleeve so as to provide an annular space therebetween, a column of projectiles within the space confined between the jacket and sleeve, and means overlying and underlying said space for supporting and confining the column of projectiles therein, each projectile having a substantially spher- Mal-"body of frangible material adapted to burst and disintegrate upon penetration of a well wall.

7. li'shell for treating wells as set forth in claim 6 including, a cylindrical coupling surrounding the lower portion of the jacket and depending therefrom for receiving the upper portion of the jacket 01 a second shell whereby two shells may be coupled to each other.

8. A shell for cleaning the producing surface or an oil well includin a tubular enclosure, an explosive charge extending longitudinally of and disposed concentrically within and spaced from the enclosure so as to provide a substantially annular space therebetween, a substantially annular column of projectiles within said space, each projectile having a substantially spherical solid body of frangible material more fragile than metallic projectiles so as to burst and entirely disintegrate upon initial penetration of the wall of the well.

JULIUS G. BURCH.

REFERENCES CITED The following references are of record in the file of this patent:

imrrnn s'ra'rns PATENTS 

